Intrusion alarm for windows and other openings

ABSTRACT

An alarm device for preventing an intruder from entering a window or door or other opening without sounding an alarm. The alarm comprises a series of electric wires arranged to extend across the opening between housings in a physical arrangement which prevents the passage of the intruder without moving one or more of the wires. An electrical alarm system is included which provides a signal upon the cutting or moving or short circuiting of any of the wires and which also signals an attempt to move, invade or otherwise tamper with the wire supporting housings.

United States Patent Tonkowich et al. Jan. 23, 1973 1 INTRUSION ALARM FOR WINDOWS 1,452,500 4/1923 Galerman ..340 273 x AND OTHER OPENINGS 1,374,255 4 1921 Vail ..340/273 t 2,374,139 4/1945 Schriner ..340/273X {75] Inventors: William Tonkowlch; John A.

Medltzf both Franklin Lakes; Primary ExaminerDonald .l. Yusko Paul vlgnoh parslppany Assistant Examiner-Scott F. Partridge [73] Assignee: Safetech, Inc., Fairfield, NJ. Attorney-Norman N. Holland [22] Filed: Dec. 30, 1970 [57] ABSTRACT [21] Appl 02593 An alarm device for preventing an intruder from entering a window or door or other opening without [52] US. Cl ..340/273, 340/274 sounding an alarm. The alarm comprises a series of lllt- Gosh l3/08 electric wires arranged to extend across the opening Field 0f Search 200/52 D between housings in a physical arrangement which prevents the passage of the intruder without moving [56] References Cited one or more of the wires. An electrical alarm system is included which provides a signal upon the cutting or UNITED STATES PATENTS moving or short circuiting of any of the wires and 1,003,234 9/1911 Cline ..200/52D which also signals an attempt to move, invade or 9 2/1913 Bertagnolli. ..200/52 D otherwise tamper with the wire supporting housings. 2,086,405 7/1937 Darden ..200/52 D 3,051,935 8/1962 Willson ..340/273 13 Claims, 9 Drawing Figures 9 W27 ELECTRIC 22 4 J POWER SOURCE AMPLIFIER 1 ALA 1m 1 I I Q 24 L 42 53% h/ j..-

ELECTRlC RELAY INTRUSION ALARM FOR WINDOWS AND OTHER OPENINGS BACKGROUND OF THE INVENTION device. In particular, the invention provides an alarm which is relatively easily and inexpensively installed, which is completely tamperproof so that there is no way in which an intruder can gain entry even though he may have a complete knowledge of the design of the device, and which permits normal opening and closing of windows with the alarm on.

There is a rapidly increasing interest in alarm devices for protecting homes and business establishments from intrusion due to an apparent rapid increase in the number of unauthorized entrances into such places by thieves or other vandals. A variety of protective devices have been devised and installed to sound an alarm when an intrusion is attempted. Many of these devices are relatively simple so that they may be easily inactivated or otherwise bypassed by the intruder. Others of the devices are more or less tamperproof, however, they have been found to be difficult and expensive to install and have also proven unreliable and subject to numerous false alarms.

The alarm system of the present invention is completely tamperproof and at the same time is sufficiently simple so that it is reliable and easily installed particularly in a system protecting a group of windows or other openings. The alarm system in accordance with the present device may be placed either inside or outside of the protected opening without interfering with the opening or closing of the protected window. When installed on the outside ofa home or other structure, the system wiring may be kept outside of the structure thereby simplifying the connection of a large number of individual window or other guards in an interconnected electrical warning system. The system in accordance with the present invention has a form which permits it to be easily installed by relatively inexperienced personnel and which also permits the interconnection of any number of the devices with a minimum amount of drilling or other alteration of the structure walls.

Accordingly, an object of the present invention is to provide an improved intrusion alarm for windows or other openings which cannot be inactivated or bypassed by an intruder.

Another object of the present invention is to provide an intrusion alarm which may be easily applied to windows and other openings in buildings by relatively inexperienced personnel with a minimum amount of alteration of the protected structure.

Another object of the present invention is to provide a sensitive and tamperproof intrusion alarm which is simple to manufacture and to install and to maintain.

Another object of the present invention is to provide an intrusion alarm which will generate a minimum number of false alarms.

Another object of the present invention is to provide an intrusion alarm which cannot be bypassed or inactivated even by an intruder with a complete knowledge of the system design.

Another object of the present invention is to provide an intrusion alarm which may be rapidly installed on the guarded structure.

Another object of the present invention is to provide an intrusion alarm for windows which will not interfere with the normal opening and closing of the windows.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

BRIEF DESCRIPTION OF THE DRAWING A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawing, forming a part of the specification, wherein:

FIG. 1 is a front elevational view illustrating an intrusion alarm in accordance with the: invention in place on a typical window.

FIG. 2 is a vertical section view of the intrusion alarm of FIG. 1 taken along line 22 of FIG. 1.

FIG. 3 is an enlarged detailed horizontal sectional view of the upper wire housing taken along line 3-3 on FIG. 5.

FIG. 4 is an enlarged detailed horizontal sectional view of the central portion of the upper housing taken along line 4-4 on FIG. 5.

FIG. 5 is an enlarged front elevational view of the alarm partially in section.

FIG. 6 is a fragmentary enlarged perspective view partially cut away illustrating the central portions of the upper and lower housings and the connecting wires.

FIG. 7 is a fragmentary front elevational view partially cut away illustrating another embodiment of the upper housing.

FIG. 8 is a fragmentary front elevational view partially cut away illustrating a still further embodiment; and

FIG. 9 is a wiring diagram ofa preferred embodiment of the alarm system.

DESCRIPTION OF THE PREFERRED EMBODIMENT The intrusion alarm provides a serially connected pattern of wires arranged to extend across a window or other opening between spaced housings with the spacing between the wires being sufficiently small to prevent the entry of an intruder without moving or breaking the wires. The arrangement of these wires and the cooperating housings or wire: supports, as will now be described in detail, cooperates to prevent the wires from being cut, short circuited, pulled apart, or in any way tampered with without the alarm being activated. It will also be seen that the housings or supports for the wires similarly may not be moved or invaded or tampered with in any way which will permit the system to be inactivated or bypassed without activating the alarm.

FIG. 1 illustrates a typical window 1 for a dwelling or other structure 2 protected with the alarm system 3. The basic elements of the intrusion alarm system include an upper housing 4 attached to the top of the window 1 and a lower housing 5 attached to the bottom of the window 1 with the alarm wires 6 extending therebetween. The intrusion alarm system 3 illustrated in FIG. 1 has been placed on the outside of the structure 2 using a simplified attachment means for the upper and lower housings 4 and 5, as will be further described below, and permitting the connecting wiring 7 for the several units of the system to be installed on the outer surface of the building or structure 2 thereby eliminating the need for cutting numerous openings through the building walls at the individual windows or other openings.

The basic electrical circuit for the intrusion alarm system 3 will now be described with particular reference to FIG. 9 and thereafter the cooperating tamper-proofing and installing features of the system will be described in greater detail.

An alarm signal or lamp 10 or other warning element is installed at a convenient location within the protected structure including suitable terminals 11, if desired, to connect the local signal with a remotely positioned signal at a police station or other guard office. This central control essentially includes a power source 12 and a current operated relay l3 normally held in its off position by the passage of current through the relay 13 and through a series loop including the protective wires 6 at each of the guarded openings and the interconnecting wires 7 as illustrated in FIG. 9.

A portion of this closed loop 6, 7, 13 is shown to consist of a multiwire cable including a single energized wire 14 surrounded by a series of additional and grounded wires 15 (FIG. 9). These protective ground wires 15 surround the closed loop throughout its length except in certain areas of the housings 4 and 5 to prevent an intruder from jumpering or cutting into the loop to bypass or to inactivate it. The several wires 15 within the cable make penetration into it difficult and also make the selection of the energized wire 14 virtually impossible before the intruder cuts the active wire 14 or otherwise brings it into electrical contact with the protective ground wires 15. The low current and voltage required for the system permits the wires 14 and 15 in the cable 6,7 to be extremely small and permit them to be deeply embedded in their protective coatings making a physical selection or other manipulation of the wires virtually impossible without causing a short circuit between the activated wire 14 and one or more of the protecting wires 15. The electrically protective features of the system will not be described as the circuit on FIG. 9 is traced between the entry of the cable 7 at the left-hand side of the upper wire housing 4 to its exit at the right-hand side of the upper housing 4.

In the upper housing 4, the wire 14 passes over a tensioning pulley 18 and again around the left-hand alarm and wire supply pulley 17. The active wire 14 then passes around a second alarm and wire supply pulley 21 similar to the pulley 17 and then passes down to and through the lower housing 5 and a mounting switch 22 similar to switch 19. The wire 14 in alarm wire 6 then passes upwardly across the guarded window 1 to complete the protective array and passes around the pulley 21 and through an alarm switch operated by bellcrank arms 38 acting through pulleys l7 and 21. The wire 14 thus passes to final mounting switch 23 and out of the upper housing 4 as connecting cable 7 leading to the next opening to be protected. The cables 7 from the protected areas have their active wire 14 connected serially through a voltage source 12 and the solenoid of the alarm relay 13 thereby completing the serial normally energized protective loop. The terminals 24 of the relay are connected to a suitable amplifier or other coupling circuit 25 whose output is coupled directly to the alarm signal or lamp 10. The amplifier or coupling means 25 preferably includes an adjustable time delay system so that the alarm signal may be delayed for an adjustable period to eliminate false alarms produced by momentary contacts which birds or other natural objects might make with the alarm WII'CS.

The Wire Mounting Housings As illustrated in FIG. 1, several alarm wires 6 protecting the window 1 extend between the upper housing 4 and the lower housing 5. The upper housing 4 will first be generally described with particular reference to FIGS. 2 and 5.

The upper housing 4 comprises a metal box 30 with a body portion 31 for attachment to the window frame using suitable fasteners 32. The housing 4 is closed after installation with an outer cover 33 which is thereafter protected against unauthorized removal by mounting switches 16 and 23 to secure the box against removal or entry by an intruder. The alarm and wire storing pulleys 17 and 21 are rotatably mounted on suitable shafts 34 (FIG. 4) near the central portion of the housing 4. The serially connected alarm wires 6 described above are seen to be wound around the pulleys 17 and 21 permitting the lower housing 5 to be drawn downwardly and away from the upper housing 4 during installation as the alarm wires 6 unwind from these rotating pulleys l7 and 21. During installation, the lower housing 5 is drawn from the upper dash-dot position illustrated in FIG. 5 to the lowered position adjacent the bottom of the window 1. It is seen that the supply of alarm wires 6 is wound in opposite directions on the two pulleys l7 and 21 so that the connecting portion of the wire 14 between the pulleys 17 and 21, which passes through the centers of the pulleys, will not be twisted by the counter rotating pulleys during installation. The two end portions of the wire 14 which run out from the pulleys l7 and 21 to the mounting switches 16 and 23 preferably are left unconnected from switches 16 and 23 during the initial installation so that they are free to twist as the alarm wires 6 are unwound. When the lower housing 5 is fastened to the window sill, these end portions are connected as illustrated in FIGS. 5 and 9 so that the active wires are coupled to the mounting switches 16 and 23 and the outer shielding wires 15 are grounded. When the lower housing has been moved into position, the tension on the extended alarm wires 6 which now pass over the window surface may be equalized by adjusting the vertical position of the tension pulleys 18 adjustably positioned in suitable slots 36 (FIG. 5) within the upper housing 4.

An alarm indication is provided which detects even very slight movements of the alarm wires 6 which comprises the alarm switch 20 electrically coupled in the active alarm circuit. This normally closed switch 20 is opened by one or the other of two bell cranks 37 (FIGS. 4 and 6) attached to the outer ends of the pulleys 17 and 21 and having one arm 38 for engaging and opening the switch 20 and a second arm 39 coupled to a coil spring 40 under tension. The above described bell cranks 37 are disconnected from the pulleys by removing the connecting screw 41 during the above described unwinding of the alarm wires 6 from the pulleys 17 and 21. After the wires 6 have been drawn from the pulleys 17 and 21 and their tension adjusted in the manner described above, the bell cranks 37 are then attached to the pulleys 17 and 21 using the coupling screw 41 so that the switch operating arms 38 of the cranks 37 are positioned midway between the leaf spring members 42 (FIG. 6) of the alarm switch 20. It is seen that any lateral or axial movement of any of the guard wires 6 will cause rotation of the pulley 17 or 21 around which that alarm wire 6 runs. This rotation of the pulley causes a corresponding rotation of the attached bell crank 37 causing the bell crank switch operating arm 38 to engage either the upper or lower leaf spring 42 to open the alarm switch contacts 43.

A preferred embodiment of the positioning switch 23 for the upper housing 4 is illustrated in FIGS. 2 and 3. The switch 23 comprises a pair of spaced leaf springs 50 and 51 each having an electric contact 52 at its end so that an electric circuit runs between the leaf spring members 50 and 51 when the switch is closed by the engagement of the movable button 53 against the window frame and movable button 54 by the housing cover 33. A recess 56 is provided in the body 31 of the upper housing 4 to receive the button 53 to make the head of the button inaccessible to an intruder thereby making it difficult to remove the housing 4 from the window 1 without permitting the button 53 to move and the contacts 52 to open. It is seen that either removal of the housing 4 from the window or the cover 33 from the housing 4 will activate the alarm.

As best illustrated in FIGS. 2 and 5, a metal electrically conducting inner shield 55 is provided in the upper housing 4 to prevent unauthorized tampering with the elements in the housing 4. This shield 55 is electrically coupled to the active wire 14 so that an attempt to cut through the housing will result in a short between the grounded housing and the energized shield thereby cutting off the relay 13 current and touching off the intrusion alarm.

As illustrated in FIG. 1, the alarm wires 6 extend from the above described upper housing 4 to a lower housing 5 attached to the lower portion of the window 1 frame. This lower housing 5 contains the connections between the lower ends of the alarm wires 6 already described above in the description of the circuit.

A preferred embodiment of the lower housing 5 is best illustrated in FIGS. 2, 5 and 6. It comprises a hollow metal box 60 through which the connecting portions 14 and of the alarm wires 6 run. It also includes mounting switches 19 and 22 at opposite ends. As seen in FIG. 2 switch 22 has an outwardly projecting button 61 which engages the adjacent surface 62 of the window frame when the housing 5 is in place to remain closed to thereby complete the series circuit through this portion of the system. The button 61 is seen to be positioned within a recess 63 to facilitate the closing of the switch by the surface of the window and to limit access to the switch by an intruder who is attempting to tamper with the system.

Spaced mounting holes 64 (FIG. 5) are provided to attach the lower housing 5 to a pair of screws 65 inserted into the window frame.

In order to make it impossible for an intruder to gain access to the circuit wires 14 or 15 or the switches 19 and 22 within the housing 5, the hollow lower housing box 60 is preferably completely filled with a flowed-in plastic or other sealant 66. Since the intrusion alarm is furnished with the upper and lower housings 4 and 5 preconnected and ready for installation, the lower housing cover 67 may be welded or otherwise tightly attached to box 60 at its point of manufacture. This tight attachment together with the wire covering plastic and mounting switches 19 and 22 make the lower housing completely tamperproof.

FIG. 7 shows an alternate embodiment of the intrusion alarm having a differing upper alarm wire support and alarm wire movement indicating means 70. The differences in the system are limited to the central portion of the upper housing 71 as illustrated in FIG. 7. The wire supply pulleys and tensioning pulleys are replaced by a generally horizontal and electrically conductive alarm bar-72. The alarm wires 73 which are run in the same manner as described above for wires 6 and for the portions not illustrated have their portions within the upper housing 71 passing through vertical apertures 74 in the alarm bar 72. The upper housing 71 and a lower housing 5 are supplied as a unit with a sufficient length of the alarm wires 73 to permit the upper and lower housings to be placed on the window with the necessary spacing. After the housings are placed, the vertical alarm wires 73 are drawn under tension and are fastened to the alarm bar 7.2 using the adjusting screws 75. The alarm bar 72 is held upwardly against the restraint of the alarm wires 73 by compressed coil springs 76 surrounding insulated guide posts 77. These guide posts 77 together with the springs 76 are made of non-conducting material or are otherwise insulated from the side walls of the upper housing 71 so that there is no electrical circuit between bar 72 and the metal housing 71. After the alarm bar 72 has been adjusted to the generally horizontal position as illustrated, a fine adjustment is made of upper and lower adjustable electric contacts 78 and 79 mounted on a conductive bracket 80 which is electrically isolated from the housing 71. It will be seen that movement of any of the four alarm wires 73 will move the conductive alarm bar 72 upwardly or downwardly into contact with one of the contacts 78 or 79 thereby completing an electric circuit between the circuit wires 81 and 82 which are coupled to an alarm activating latching relay (not shown). Wires 73 include an active series circuit and guarding ground wires similar to those described for the embodiment of FIGS. 1-6 and 9.

FIG. 8 illustrates an additional embodiment also similar to the above described embodiment of FIGS. 1-6 with the exception of the central alarm contact which occupies the central portion of the upper housing 91 as illustrated in FIG. 8.

In this embodiment, the pulley and bell crank alarm switch arrangement of FIGS. 1-6 and 9 is replaced by an elongated generally horizontal alarm bar 92. The vertical guard wires 93 which extend over the protected opening are seen to pass through apertures 94 in the bar 92. After the upper and lower housings have been placed in position on the guarded window, the guard wires 93 are placed under tension as the alarm bar 92 is moved downwardly against the force of two compression springs 95 mounted on concentric guide posts 96 which also slidably support the alarm bar 92. The set screws 97 on the bar 92 fix the wire positions so that the alarm bar 92 is in the generally central position illustrated permitting the adjusting screws 98 to be set so that the two alarm contacts 99 remain closed. Should the alarm bar 92 be made of electrically conducting metal, it is electrically isolated from the upper housing either by insulating the adjusting screw 98 or the guide posts 96. The two alarm contacts 99 are wired in series with the energized wire within the guard wires 93. Movement of any of the guard wires 95 will rock the alarm bar 92 causing one or both of the alarm contacts 99 to open thereby energizing the alarm circuit by causing a latching relay means to close to provide an alarm signal.

An inner protective shield similar to the shield 55 described for the embodiment of FIGS. 1 through 6 may be used in the embodiments illustrated in FIGS. 7 and 8.

The springs 76 and 95 are preferably provided with differing spring values for differing housings to further tamperproof the system by preventing the application of substitute weights on springs on the guard wires 73 or 93.

It will be seen that an improved intrusion alarm and alarm system have been provided for giving a sure warning of an attempt to enter into a dwelling or other structure. The improved system is completely tamperproof and, at the same time, permits the occupant of the protected structure to open and close the windows or other openings in the normal fashion without the alarm system having to be turned off. This feature together with the improved arrangement of the protective alarm wires and their mounting means provides for a significant reduction in the chances of generating false alarms.

Additionally, the improved intrusion alarm in accordance with the present invention is particularly adapted for each installation with most parts being prewired and supplied to the user in a form ready to be easily applied to the guarded structure. The alarm wire housing means and the cooperating electrical system further simplifies installation by permitting substantially the entire cable or connecting system to be run outside of the guarded structure thereby limiting the requirement for a large number of cable openings in the walls and the need for interior conduits.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all mater herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. An alarm system for protecting an opening in a member comprising the combination of:

a first housing for being mounted at one side of the opening;

a second housing for being mounted at an opposite side of the opening;

a plurality of electrically conducting alarm wires extending in spaced relation across the opening and between said housings;

conducting means within the housings connecting said alarm wires;

pulley means within one of said housings;

said alarm wires at least partially encircling said pulley means whereby movement of one or more of said wires turns the pulley means;

an electrical switch positioned in said first housing adjacent to said pulley means;

means releasably coupling said pulley means to said electrical switch whereby when uncoupled the alarm wires may be drawn from the pulley means and whereby when coupled a movement of the pulley means by the alarm wires actuates said switch;

an electrically actuated alarm means; and

means coupling said alarm wires and said switch to said alarm means whereby the activation of said switch or the disruption of said coupling means actuates the alarm means.

2. The alarm system as claimed in claim 1 in which said pulley means comprises a plurality of pulleys each being at least partially encircled by a plurality of alarm wires.

3. The alarm system as claimed in claim 2 in which said pulley means comprises a pair of pulleys mounted for rotation in opposite directions by said alarm wires and with a portion of said conducting means running between the two pulleys.

4. The alarm system as claimed in claim 1 in which said releasable coupling between said pulley means and said electrical switch comprises a crank.

5. The alarm system as claimed in claim 3 in which said releasable coupling means comprises a crank on each pulley having an arm engaging said switch.

6. The alarm system as claimed in claim 1 which further comprises switch means in said housings engaging the member adjacent to the opening and activated by a detachment of either of said housings from said member.

7. An alarm system as claimed in claim 1 in which the alarm wires each include a plurality of individual conductors with one of said conductors being coupled to the alarm means and with the other conductors being electrically grounded.

8. An alarm system as claimed in claim 6 which further comprises a flowed-in sealing material in said second housing enveloping said said conducting means and said switch means in said second housing.

9. An alarm system for protecting an opening in a member comprising the combination of:

a first housing for being mounted at one side of the opening;

a second housing for being mounted at an opposite side of the opening;

a plurality of electrically conducting alarm wires extending in spaced relation across the opening and between said housings;

conducting means within the housings connecting said alarm wires;

pulley means within one of said housings;

each of said alarm wires at least partially encircling said pulley means whereby movement of one or more of said wires turns the pulley means;

resilient means coupled to said pulley means placing the alarm wires under tension;

an electrical switch positioned in said first housing adjacent to said pulley means;

crank means releasably coupling said pulley means to said electrical switch whereby when uncoupled the alarm wires may be drawn from the pulley means and whereby when coupled a movement of the pulley means by the alarm wires actuates said switch;

switch means in said housings engaging the member adjacent to the opening and activated by a detachment of either of said housings from said member;

an electrically actuated alarm means; and

means coupling said alarm wires and said switch seri ally to said alarm means whereby the activation of said switch or the disruption of said coupling means actuates the alarm means.

10. An alarm system as claimed in claim 9 in which the alarm wires each include a plurality of individual conductors with one of said conductors being coupled to the alarm means and other conductors being grounded.

11. An alarm system as claimed in claim 9 which further comprises a flowed-in sealing material in said second housing enveloping said conducting means and said switch means in said second housing.

12. An alarm system for protecting an opening in a wall comprising the combination of:

a first housing for being mounted at one side of the opening;

a second housing for being mounted at an opposite side of the opening;

a plurality of electrically conducting flexible alarm wires extending in spaced relation across the opening and between said housings;

conducting means within the housings connecting said alarm wires;

a unitary elongated bar within the first of said housings; said alarm wires being adjustably physically coupled to said bar at spaced locations whereby movement of one or more of said wires moves the bar;

resilient means engaging and positioning said bar and placing said alarm wires under tension;

an electrical switch positioned in said first housing adjacent to said bar for actuation by bar movement; said second housing all being filled with flowed-in sealing compounds; an electrically actuated alarm means;

each of said alarm wires comprising a plurality of conductors with one of said conductors of each wire being coupled serially to one conductor of all other of said wires and the other conductors of each wire being grounded; and

means coupling said serially connected conductors and said switch to said alarm means whereby the activation of said switch or the opening or grounding of said serial connection actuates the alarm means.

13. An alarm system as claimed in claim 12 which further comprises switch means in said first and second housings engaging the wall adjacent the opening and activated by a detachment of either of said housings from said wall, and said switch means being included in said coupling means whereby removal of either of said housings from said wall activates the alarm means. 

1. An alarM system for protecting an opening in a member comprising the combination of: a first housing for being mounted at one side of the opening; a second housing for being mounted at an opposite side of the opening; a plurality of electrically conducting alarm wires extending in spaced relation across the opening and between said housings; conducting means within the housings connecting said alarm wires; pulley means within one of said housings; said alarm wires at least partially encircling said pulley means whereby movement of one or more of said wires turns the pulley means; an electrical switch positioned in said first housing adjacent to said pulley means; means releasably coupling said pulley means to said electrical switch whereby when uncoupled the alarm wires may be drawn from the pulley means and whereby when coupled a movement of the pulley means by the alarm wires actuates said switch; an electrically actuated alarm means; and means coupling said alarm wires and said switch to said alarm means whereby the activation of said switch or the disruption of said coupling means actuates the alarm means.
 2. The alarm system as claimed in claim 1 in which said pulley means comprises a plurality of pulleys each being at least partially encircled by a plurality of alarm wires.
 3. The alarm system as claimed in claim 2 in which said pulley means comprises a pair of pulleys mounted for rotation in opposite directions by said alarm wires and with a portion of said conducting means running between the two pulleys.
 4. The alarm system as claimed in claim 1 in which said releasable coupling between said pulley means and said electrical switch comprises a crank.
 5. The alarm system as claimed in claim 3 in which said releasable coupling means comprises a crank on each pulley having an arm engaging said switch.
 6. The alarm system as claimed in claim 1 which further comprises switch means in said housings engaging the member adjacent to the opening and activated by a detachment of either of said housings from said member.
 7. An alarm system as claimed in claim 1 in which the alarm wires each include a plurality of individual conductors with one of said conductors being coupled to the alarm means and with the other conductors being electrically grounded.
 8. An alarm system as claimed in claim 6 which further comprises a flowed-in sealing material in said second housing enveloping said said conducting means and said switch means in said second housing.
 9. An alarm system for protecting an opening in a member comprising the combination of: a first housing for being mounted at one side of the opening; a second housing for being mounted at an opposite side of the opening; a plurality of electrically conducting alarm wires extending in spaced relation across the opening and between said housings; conducting means within the housings connecting said alarm wires; pulley means within one of said housings; each of said alarm wires at least partially encircling said pulley means whereby movement of one or more of said wires turns the pulley means; resilient means coupled to said pulley means placing the alarm wires under tension; an electrical switch positioned in said first housing adjacent to said pulley means; crank means releasably coupling said pulley means to said electrical switch whereby when uncoupled the alarm wires may be drawn from the pulley means and whereby when coupled a movement of the pulley means by the alarm wires actuates said switch; switch means in said housings engaging the member adjacent to the opening and activated by a detachment of either of said housings from said member; an electrically actuated alarm means; and means coupling said alarm wires and said switch serially to said alarm means whereby the activation of said switch or the disruption of said coupling means actuates the alarm means.
 10. An alarm system as claimed in claim 9 In which the alarm wires each include a plurality of individual conductors with one of said conductors being coupled to the alarm means and other conductors being grounded.
 11. An alarm system as claimed in claim 9 which further comprises a flowed-in sealing material in said second housing enveloping said conducting means and said switch means in said second housing.
 12. An alarm system for protecting an opening in a wall comprising the combination of: a first housing for being mounted at one side of the opening; a second housing for being mounted at an opposite side of the opening; a plurality of electrically conducting flexible alarm wires extending in spaced relation across the opening and between said housings; conducting means within the housings connecting said alarm wires; a unitary elongated bar within the first of said housings; said alarm wires being adjustably physically coupled to said bar at spaced locations whereby movement of one or more of said wires moves the bar; resilient means engaging and positioning said bar and placing said alarm wires under tension; an electrical switch positioned in said first housing adjacent to said bar for actuation by bar movement; said second housing all being filled with flowed-in sealing compounds; an electrically actuated alarm means; each of said alarm wires comprising a plurality of conductors with one of said conductors of each wire being coupled serially to one conductor of all other of said wires and the other conductors of each wire being grounded; and means coupling said serially connected conductors and said switch to said alarm means whereby the activation of said switch or the opening or grounding of said serial connection actuates the alarm means.
 13. An alarm system as claimed in claim 12 which further comprises switch means in said first and second housings engaging the wall adjacent the opening and activated by a detachment of either of said housings from said wall, and said switch means being included in said coupling means whereby removal of either of said housings from said wall activates the alarm means. 